Abstract: An ammunition cartridge for a gun is optically initiated by a mechanism wholly within the cartridge case itself. The case has as optical primer initiation means producing light fluence to ignite a primer, which ignited primer may in turn ignite into a flashtube, and which ignited flashtube may in turn ignite a bed of propellant in said cartridge. The optical primer initiation means may be an LED, a laser diode, a VCSEL, or some other light emitting device in general. The cartridge optically initiated primer package is so sized and made electrically and mechanically seamlessly physically compatible with current ammunition cartridges such that these new cartridges are completely interchangeable.